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Biomedical subjects

R F Taylor

Publications and source records attributed to R F Taylor.

At least 37 records · Page 2Linked to original sources
PubMed1991

Effect of heart-lung transplantation on airway potential difference in patients with and without cystic fibrosis.

Measurement of the potential difference (PD) across the airways provides an indication of the viability and integrity of the lining epithelium. PD was recorded from the lower airways in "diseased controls" and in patients following heart-lung transplantation. Diseased controls showed a high PD centrally which fell (became less negative) peripherally (trachea -15.8 mV (SEM 1.0), lobar bronchi -12.6 mV (1.2), segmental bronchi -9.8 mV (1.2]. Following heart-lung transplantation (HLT) the profile of PD with airway size was altered in comparison to non-transplanted patients with reduced values in the large airways. Host tracheal values above the anastomosis were similarly reduced. Two episodes of rejection were associated with a lower mean airway PD; no significant changes were found with infection. In patients with cystic fibrosis (CF), values in the donor lung did not differ from those in non-CF transplanted patients up to one year following transplantation, although nasal PD in the host remained elevated. HLT selectively alters the PD profile only of larger airways, which may relate to the interruption of the bronchial arterial supply to these sites.

Biological Transport, Active↗
PubMed1990

Specialized gastrointestinal units for the management of upper gastrointestinal haemorrhage.

In 1986, 292 patients were admitted to a joint medical-surgical gastrointestinal unit with upper gastrointestinal haemorrhage. Fourteen patients died (4.8%) a mortality considerably lower than recorded in most series. The low mortality may result from the use of a specialized gastrointestinal unit to which all patients with upper gastrointestinal haemorrhage are admitted and managed with strict protocols for resuscitation, transfusion and surgery.

Aged↗
PubMed1990

Chronic cervical spinal cord injury and autonomic hyperreflexia in rats.

Although it is well established that patients with cervical spinal cord injury are prone to acute, marked, hypertensive episodes, i.e., autonomic hyperreflexia, the specific mechanisms mediating this sometimes-fatal phenomenon are not completely understood. In this report, we describe the preparation and characterization of a rat model of chronic cervical spinal cord injury and autonomic hyperreflexia. Adult male Sprague-Dawley rats were chronically instrumented with arterial, venous, and gastric catheters. Beginning the first day after a complete cervical spinal transection (CST) and continuing for 1 wk, acute hypertensive responses to a modest increase of urinary bladder pressure (0-20 mmHg) were studied. Mean arterial pressure increased 25.9 +/- 4.8 mmHg during bladder distension the first day after CST. This response was not significantly different 3, 5, and 7 days after CST (overall average = 18.0 +/- 2.3 mmHg). The pressor response to bladder distension was completely abolished by intravesical lidocaine and autonomic ganglionic blockade (atropine + hexamethonium). Responses to bladder distension were not observed after the administration of chloralose anesthesia. We conclude that after cervical spinal transection the rat exhibits autonomic hyperreflexia similar to that seen in humans with spinal injury. Furthermore, autonomic hyperreflexia is completely established within 24 h after CST in the rat. Finally, some spinal autonomic reflexes are suppressed by chloralose anesthesia in the rat.

Animals↗
PubMed1989

The management of children born to human immunodeficiency virus seropositive women.

Increasing numbers of children born to human immunodeficiency virus (HIV) antibody-positive women are being identified, but guidelines as to their management are lacking. We have therefore established a paediatric counselling and screening clinic for managing such children in Edinburgh. During a period of 3 years, 49 infants and children of 43 HIV seropositive women have been seen. After a median follow-up period of 23 months, four children were found to have clinical evidence of HIV disease which was non-specific and could have been missed had they not been regularly monitored. Thus, close surveillance of infants born to seropositive women is important. Identifying a single clinic where this is done has allowed experience to accumulate on issues beyond the medical management of these infants as well as contributing to the clinical care of infants with symptoms. Based on this experience, we have developed guidelines for managing children born to HIV antibody-positive women.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Determinants of arterial pressure after chronic spinal transection in rats.

The present study was conducted to determine whether sympathetic vasoconstrictor activity is a determinant of mean arterial pressure (MAP) hours and days after cervical spinal transection (CST) in unanesthetized rats. MAP on the 2 days before CST was 107.2 +/- 3.6 and 103.3 +/- 3.0 mmHg, respectively, and fell to 77.7 +/- 1.1 mmHg on day 1 after CST. MAP returned to control levels over the course of the study and, by day 9 after CST, was not statistically different from control (98.6 +/- 3.4 mmHg). Neither autonomic ganglionic blockade nor alpha-adrenergic blockade affected MAP the 1st day after CST. Similarly, alpha-adrenergic blockade was without effect on days 3, 5, and 7 after CST. Administration of a vasopressin V1-antagonist had no effect on MAP on day 1 or day 8 after CST. However, blockade of angiotensin-converting enzyme with captopril decreased arterial pressure both on day 1 (-22.1 +/- 2.6 mmHg) and day 8 (-23.3 +/- 2.9 mmHg) after CST. We conclude that neither sympathetic nor vasopressin vasoconstrictor activity affected MAP within the 1st wk after CST. Although the vasoconstrictor actions of angiotensin II were important, these effects were not responsible for the normalization of MAP observed after CST.

Angiotensin II↗
PubMed1989

Airway complications from free-basing cocaine.

The majority of the deaths due to fires result from smoke inhalation, hypoxia, and systemic toxicity. Lower airway injury from chemical byproducts carried in the smoke is less frequent and thermal injury to the lower airways is a rare occurrence. We report a case of severe thermal injury to the conducting airways due to either inhalational injury or to intratracheal ignition of the ether vehicle used in free-basing cocaine resulting in severe reactive airways disease and tracheal stenosis requiring reconstructive surgery.

Adult↗
PubMed1988

Transcoronary platelet activation and consumption in coronary artery disease: studies at rest.

The platelet count(PC), plasma platelet factor 4 (PF4) and plasma beta-thromboglobulin(beta TG) have been measured in blood obtained from a peripheral vein, the aortic root and the coronary sinus in 7 patients with normal coronary arteries, 9 patients with lesser degrees of coronary artery disease(CAD) and in 13 patients with severe CAD under resting conditions. In each patient group values obtained in the peripheral venous blood were similar to those obtained in normal subjects. In each group values obtained in blood from the coronary sinus were similar to those obtained in blood from the coronary aortic root and in most instances these were similar to values obtained in peripheral venous blood. for example, in the 13 subjects with hemodynamically significant 3-vessel or 2-vessel CAD the mean values in blood from a peripheral vein, the aorta and the coronary sinus respectively were: PC-194, 205, and 208 x 10(9)/1; PF4-3.3, 3.7, and 3.5 ng/ml; and beta TG-15.5, 23.0 and 18.6 ng/ml. These findings provide no support for the occurrence of continuous platelet activation or platelet consumption in the coronary vessels or elsewhere in patients with stable CAD, under resting conditions, regardless of its severity.

Coronary Disease↗
PubMed1988

Sudden and unexpected death in horses and ponies: an analysis of 200 cases.

An analysis was made of the causes of death in horses and ponies over one year of age which died suddenly (Group 1) or were found dead but were considered normal when last seen (Group 2). There were 49 animals in Group 1. Thoroughbreds were overrepresented, but there were no ponies in this group. No cause of death was found in 30.6 per cent of cases and 16.3 per cent died from each of the following causes: haemorrhage in the respiratory system, central nervous system, and adverse drug reactions. Cardiovascular lesions were the cause of death in 14.4 per cent and the remaining 3.1 per cent had lesions of the gastrointestinal system. Racehorses mostly died suddenly from severe haemorrhage in various sites, particularly the thorax. In Group 2 there were 151 animals, and in 33.1 per cent no cause of death was determined. Gastrointestinal lesions were considered the cause of death in 39.2 per cent of cases and respiratory lesions killed 8.6 per cent. Lesions of both the central nervous system and cardiovascular system were considered the cause in 4.6 per cent of cases. The remaining 9.9 per cent of animals had miscellaneous lesions. Toxicological studies were performed in 46 of the total 200 cases, and only two had positive results; lead in one and nicotine in the other.

Age Factors↗
PubMed1988

Spinally mediated inhibition of abdominal and lumbar sympathetic activities.

Renal, splenic, and lumbar sympathetic nerve activities were recorded in the paralyzed, anesthetized, artificially ventilated, and spinally transected rat. Electrical stimulation of the dorsolateral funiculus caudal to the spinal transection was used to generate stimulus-response curves for changes in sympathetic activity in each of the three sympathetic nerves using five stimulus frequencies. In all rats, spinal stimulation inhibited sympathetic activity in renal and splenogastric nerves by approximately 50%. In grouped data, threshold frequency for inhibition of renal and splenogastric sympathetic nerve activity was 5 Hz, and inhibitions were maximal (50-60%) at 10 Hz. In contrast, activity in the lumbar sympathetic chain was inhibited in only two of five rats, and grouped data did not exhibit any statistically significant inhibitions. We conclude that lumbar sympathetic activity which remains after spinal transection can be inhibited only marginally by spinal stimulation, which substantially reduces renal and splenogastric sympathetic activity.

Animals↗
PubMed1987

Differential effects of spinal transection on sympathetic nerve activities in rats.

We measured renal, splenogastric, and lumbar multiunit sympathetic activities in chloralose-anesthetized, paralyzed, and artificially respired Sprague-Dawley rats. Acute spinal transection reduced arterial pressure and lumbar sympathetic activity. However, renal and splenogastric activities were doubled after transection. We conclude that spinal systems exist in the rat that are capable of maintaining renal and splenogastric, but not lumbar, sympathetic activities after spinal transection. Cross-correlation and power spectral analysis of simultaneously recorded sympathetic activities indicated that renal and splenogastric activities often, but not always, shared periodicities near the respiratory rate. These shared periodicities were responsible for high correlations between renal and splenogastric activities. After spinal transection, the shared periodicities usually disappeared, and correlations were reduced. Renal and lumbar activities were rarely strongly correlated, and they rarely shared major periodicities. We conclude that brain stem systems often provide synchronization of abdominal sympathetic activities. However, these activities can be independently generated in both intact and spinally transected rats.

Animals↗
PubMed1987

Pilot trial of prolonged continuous-infusion 5-fluorouracil and weekly cisplatin in advanced colorectal cancer.

Thirty-five patients with previously untreated, advanced, measurable metastatic colorectal carcinoma were treated with a 12-week course of continuous 5-fluorouracil (5-FU) and weekly cisplatin. Twenty of 32 evaluable patients responded (five complete and 15 partial responses), for an overall response rate of 63% (90% confidence limits, 43%-75%). Toxicity was generally mild and reversible and included mucositis (40%), painful erythema of the palmar and plantar skin (30%), diarrhea (21%), nausea and vomiting (15%), and leukopenia (6%). One patient died of sepsis secondary to mucositis and myelosuppression. This program is a well-tolerated outpatient regimen for metastatic colorectal carcinoma. The response rate is higher than expected for 5-FU and cisplatin and suggests clinical therapeutic synergism at this dose rate and schedule.

Adult↗
PubMed1986

Effect of nicotine aerosol on slowly adapting receptors in the airways of the dog.

The response of slowly adapting airway stretch receptors to nicotine aerosol was studied in the paralyzed, artificially ventilated, anesthetized dog. Single-unit stretch receptor recordings were made from individual vagus nerve filaments placed on a pair of platinum hook electrodes. Administration of 2% nicotine aerosol for five consecutive breaths caused an increase in both the peak transpulmonary pressure (Ptp) and in the activity of the slowly adapting stretch receptors (SARs). The results suggest that tracheal SARs were more affected than those receptors located distal to the carina. Administration of nicotine aerosols following pretreatment with isoproterenol, a bronchodilator, failed to significantly increase Ptp and, concomitantly, the activity of SARs. Therefore, the stimulatory effect of nicotine on SARs appeared to involve primarily an indirect activation of SARs via nicotine-induced bronchoconstriction. It is suggested that the activation of SARs may be involved in the reported nicotine-dependent cigarette smoke-induced apnea.

Administration, Intranasal↗